<style name="inputDialog" parent="@android:style/Theme.Holo.Light.Dialog">
    <item name="android:windowBackground">@color/dialog_bg</item>
    <!--背景-->
    <item name="android:windowFrame">@null</item>
    <!--设置无边框-->
    <item name="android:windowNoTitle">true</item>
    <!-- 无标题 -->
    <item name="android:backgroundDimEnabled">true</item>
    <!-- 模糊 -->
    <item name="android:windowSoftInputMode">stateAlwaysVisible</item>
    <!--显示软件盘-->
  </style>

dialog.setOnKeyListener(new DialogInterface.OnKeyListener() { 
      @Override 
      public boolean onKey(DialogInterface dialogInterface, int keyCode, KeyEvent keyEvent) { 
        if (keyCode == KeyEvent.KEYCODE_BACK && keyEvent.getRepeatCount() == 0) 
          dialog.cancel(); 
        return false; 
      } 
    });